Deleting Catalytic Converters 1994 FZJ80

[Ninja17]

Happy, I just found this thread (on external search engine), was about to post asking same questions, regarding my '97 Land cruiser.
I did a cat delete on my '88 4Runner w/ 22RE and it improved performance like night & day (whereas a high-flow cat did nothing), and it actually passed emissions for 3 yrs straight until a garage doing inspection noticed it missing (after saying it had passed emissions) , then flagged it the state computer and denied my inspection.

Anyway, where I live now an inspection/ emissions check is not required, only a visible muffler and spark arrestor , I just wasn't sure if I would see some improvement and/or encounter issues on my 80 series. I am going to weld in a straight pipe like photo above, hopefully see some improvement, whilst keeping the cat thieves at bay.

 

[BILT4ME]

Happy, I just found this thread (on external search engine), was about to post asking same questions, regarding my '97 Land cruiser.
I did a cat delete on my '88 4Runner w/ 22RE and it improved performance like night & day (whereas a high-flow cat did nothing), and it actually passed emissions for 3 yrs straight until a garage doing inspection noticed it missing (after saying it had passed emissions) , then flagged it the state computer and denied my inspection.

Anyway, where I live now an inspection/ emissions check is not required, only a visible muffler and spark arrestor , I just wasn't sure if I would see some improvement and/or encounter issues on my 80 series. I am going to weld in a straight pipe like photo above, hopefully see some improvement, whilst keeping the cat thieves at bay.

Cat thieves in Montana? Seems like a long drive.....

 

[Ninja17]

Cat thieves in Montana? Seems like a long drive.....

Tweakers in town, they were stealing the furry ones until they figured out they couldn't trade them for meth, and it's my grocery-getter/shopping rig

 

[Ninja17]

Update, I deleted both inline Cats on '97 80 Series, not throwing any codes, no noticeable increase in sound, no smelly exhaust, and best of all I have gained about 3 mpg !! Couldn't be more p;leased with outcome.

 

[Rifleman]

Anyone know where to get those specific flanges? I've seen some similar, but I'm not sure they're the same. The guy before me did the magnaflow front one, but didn't bother with the second and I really don't want to buy one of I'm going to swap the engine and re-do everything anyways.

I know this is an old thread, but for any one thinking about making a set of test tubes i think this info might be helpful,

To answer the above question, i looked on line and couldn't find anything that was even close to the factory flanges so i ended up making a set,

Sorry for the small photos but I'm unable to get my phone to enlarge them, Now unless you're going to cut the factory flanges off of your old cat, and reuse them, you'll have to make your own set,

Now here are the problems you'll need to deal with if you make your own set, In the first photo you'll notice small pieces of pipe sticking out of the factory head, and Y pipes that you need your new flanges to mate up with,

Along with those small pieces of pipe that help locate the exhaust gasket, also notice that the mating face of the factory flanges are counter bored ,085 thousands of an inch to hold and locate the exhaust gaskets too,

If you fab your own set of flanges you'll need to make sure that you counter bore your flanges to make room for those small pieces of pipe that stick out from the face of the factory exhaust system, along with making room for the gaskets too,

In the case of the inlet side flange you only need one counter bore for the gasket, this is due to the fact that the small piece of pipe sticking out from the head pipe is 2 1/4 inches in diameter same as the bore in the flange,

Take note the flange on the outlet side of the cat is different then the inlet side, and needs not 1, but 2 stepped down counter bores, one for the gasket, and one for the small piece of pipe to fit into, This is due to the fact that the Y pipes small pieces of pipe are larger in diameter, and stick out farther then the head pipe does,

In the second photo you can see the 1/2 inch thick steel flat stock i made the flanges from, In the third photo you can see that the flange has been faced off so it is flat, and the 2 1/4 inch through bore and counter bore for the gasket has been machined,

In the forth photo you can see a finished inlet side flange, note i made the I D of the flange ,001 of an inch under size so i could press fit the 2 1/4 inch exhaust tube into the flange before welding,

In the last photo you can see the finished set of test tubes with the new flanges welded in place, one last item, if you are going to fab a set for yourself, the finished OAL length of the test tubes is 12 1/2 inches long, same length as the cats they would be replacing during testing,

 

[Rifleman]

Just wanted to give everyone an update, I know some members wanted to know if removing their cats, and installing a set of test tubes would make any difference in performance,

Well i took my truck for a 200 mile test drive after removing my cats and installing test tubes in their place, This test drive was done on an up, and down hill 2 lane road, speeds running anywhere between 45 MPH to 70 MPH,

Before starting my test i filled up my gas tank, and upon returning home i filled it up again, I use to get 9 to 10 miles per gallon, and my water temps ran between 180 to 185 degrees, My water temp gauge is plumbed in on the engine outlet side of the upper radiator hose,

Results from my test, my gas mileage went from 9 to 10 miles per gallon, to 14,75 miles per gallon, My water temps decreased and are now running between 170 and 178 degrees,

Now this last item i can't quantify with any real hard performance data, but, and it's a BIG BUT, When i pulled out to pass people who were pulling trailers my truck seemed to have more get up and go when i pushed the go peddle to the floor,

One last item I'd like to state before anyone asks, my Cats were NOT plugged, or damaged in anyway, they were nice and clean inside, I just wanted to see if removing the cats made any difference, with the testing now over I'm reinstalling my old factory cats,